脳神経外科速報

最新の知見をもとに，くも膜下出血（SAH）後の脳血管攣縮をはじめとしたさまざまな病態とその治療について述べる．

脊索腫は罹患率10万人対0.08人程度と稀な腫瘍であり，頭蓋底原発のものはその4 割程度を占める．遺残脊索より発生するとされ，免疫染色にてbrachyury陽性となることは診断的価値が高い．外転神経障害に伴う複視で発症することが多い．画像上は，典型的にはT2高信号を示す骨破壊性の斜台部腫瘍である．外科的切除が治療の根幹を成し，近年拡大経蝶形骨洞法が選択されることが多い．術中に内頚動脈や脳神経の近傍での操作となることが多く，脳神経機能モニタリング，超音波ドプラ，ナビゲーションなどを活用して安全に配慮すべきである．摘出中には海綿静脈洞や脳底静脈叢などからの出血を認めることが多く，止血手段を整えておく．再発の多い腫瘍であり放射線治療の必要性は高く，陽子線・重粒子線・ガンマナイフなどが選択肢となる．本稿では頭蓋底脊索腫に焦点を当て，最新のエビデンスを交えて概説する．

Atlantoaxial osteoarthritis (AAOA) has been recognized as a distinct cause of occipitocervical pain in older adults. Recently, we experienced the case of a patient with AAOA accompanying occipital neuralgia (ON). Because of its rarity and difficulty in devising a treatment strategy, this case is reported alongside a review of literature. A 75-year-old woman presented with a 12-month history of electric shock-type pain radiating from the left suboccipital region to the vertex, which was aggravated by neck motion especially when the head was rotated to the left. She also complained of chronic left-sided neck pain, which developed 5 years before the onset of neuralgia. Her condition responded minimally to treatment with a soft collar and analgesic drugs. Under fluoroscopic control she underwent injection of local anesthetic and steroid agents to the C-2 nerve root, which provided immediate relief of electric shock-type pain for 5 days, although the effect was minimal for chronic neck pain. For this patient C2 neurectomy and C1-2 fusion was performed. Her postoperative course was favorable.

Distal superior cerebellar artery (SCA) aneurysms are rare, and intracranial aneurysms as a complication of radiotherapy are particularly rare. We report a distal SCA aneurysm after gamma knife radiosurgery (GKRS) for trigeminal neuralgia (TN). An 83-year-old male patient presented with severe headache and vomiting associated with conscious disturbance. He had undergone GKRS for TN 14 years ago, and facial pain was ameliorated after the treatment. On admission, CT scan showed subarachnoid hemorrhage with thick clots in the left cerebellopontine cistern and 3D-CTA showed a left distal SCA aneurysm. Although we treated the aneurysm with complete coil embolization, he died of re-rupture of the aneurysm on postoperative day 19. Our patient had previous GKRS for TN that we suspect ultimately led to a distal SCA aneurysm. Radiation-associated intracranial aneurysm is a rare complication, and its frequency as well as optimal treatment is still controversial. Delayed development of aneurysm is a recognized long-term complication of GKRS, and it may be an overlooked complication with potentially devastating outcome. To the best of our knowledge, this is the second case of aneurysm as a late complication of GKRS reported in the literature.